Abstract
It has been shown that in Lumbricus1 and Nereis2 the anterior segments of the animal respond to passive bending of the posterior part, by active turning of the head in a direction parallel with the new orientation of the tail. This has been termed the homostrophic reflex. The receptors for the reflex are distributed throughout the animal but the efferent nerves are limited in their origin to the anterior 20 segments in Lumbricus, and to the first 2 or 3 segments in Nereis. The afferent impulses travel forward by way of the ventral nerve cord. Bending of the head end does not affect the direction of backward locomotion, hence the mechanism of the homostrophic reflex exhibits polarity. Similar observations3 have been recorded for Diplopods and for the larvae of Tenebrio molitor.A systematic study has shown the homostrophic reflex to play a part in the behavior of a number of nereid worms of the Mediterranean, namely, Eunice gigantea, Eunice siciliensis, Holla parthenospeia, Nephthis scolopendroides, Sthenela...
Published Version
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